The iPhone Dev-Team released RedSn0w 0.9.14b2 with improved algorithm for baseband downgrade from the iPad's 06.15 baseband to 05.13 on the iPhone 3GS and iPhone 3G. The 06.15 baseband was used by many users to unlock their device. Now it is possible to to get back true GPS and an ultrasn0w unlock.

The iPhone Dev-Team released RedSn0w 0.9.14b1 that can perform a baseband downgrade from the iPad's 06.15 baseband to 05.13 on the iPhone 3GS and iPhone 3G. The 06.15 baseband was used by many users to unlock their device. Now it is possible to to get back true GPS and an ultrasn0w unlock.

iPhone Dev Team have just released a new version of RedSn0w 0.9.10b4. It includes a fixes for iBooks and launchctl. As always, you can simply run the new redns0w over your current jailbreak, just make sure to uncheck Cydia. To fix iBooks and launchctl errors you can also simply install new version of Corona from Cydia.

1. If you're already on iOS 5.0.1 with a tethered jailbreak, you have two even choices:

Run redsn0w 0.9.10 over your current jailbreak (deselect “Install Cydia”)

Install the Cydia package prepared by the chronic devteam. It is called Corona 5.0.1 Untether. (tutorial)

2. If you are not on 5.0.1 yet, update now! If you unlock via ultrasn0w or gevey, make sure you update to 5.0.1 via a custom IPSW! See our guides for sn0wbreeze here. Once you're at 5.0.1, use the latest redsn0w 0.9.10 to both jailbreak and untether.

UPDATE: Apple released new iOS versions and has stopped signing all other firmwares, including iOS 6.1.2 and iOS 5.1.1. This means you can NOT restore to 6.1.2/5.1.1/4.3.3 and others any more (both original and custom), unless you have saved your SHSH keys for it.

If you have decided to perform an untethered jailbreak and unlock, you need to get the following information:

What type of device do you have (iPhone 3G/3GS/4, iPod Touch 3G/4G, iPad 1/2, Apple TV)?

Do you need unlock (if your iPhone locked to one carrier and you want to use it with another)?
The answer is NO, if the device is not iPhone, if it was purchased as factory unlocked and can be used with any cellular carrier (f.e. in Canada, France, etc).
If the answer is YES, you need to find out your modem version (Setting-General-About-Modem).

What firmware version do you have? Take a look at Setting-General-About-Version. For example it could be iOS 4.3.3.

What operating system do you use on your desktop (Windows, Mac OS)?

How to perform jailbreak, when you do NOT need an unlock

For iPhone 3G the latest is iOS 4.2.1. You can perform jailbreak with any utility. For iOS 4.2.1 you can also use them or GreenPois0n (Windows, Mac OS).

If you have saved SHSH keys for iOS 4.3.3 you can use PwnageTool (Mac OS) or Sn0wBreeze (Windows).

iOS 4.3.4/4.3.5

For iOS 4.3.4/4.3.5 only tethered jailbreak is possible with redsn0w. Tethered means that each time you restart your device you will have to connect it to a computer and run redsn0w. The untethered iOS 4.3.5 jailbreak is possible only for iPhone 3GS with old bootrom. You can detect your bootrom version using this tutorial.

iOS 5

To jailbreak and unlock iOS 5 use latest version of redsn0w 0.9.9 or sn0wbreeze 2.8. You can jailbreak tethered or semi-tethered.

The untethered iOS 5 jailbreak is possible only for iPhone 3GS with old bootrom. You can detect your bootrom version using this tutorial.

iOS 5.0.1

For iPhone 4/3GS, iPad 1, iPod Touch 3G/4G an untethered jailbreak is available for iOS 5.0.1. For untethered jailbreak use the latest redsn0w 0.9.10 or Corona - package from Cydia to untether currently installed tethered jailbreak.

Tutorial how to untether installed tethered jailbreak is available here.

For iPhone 4S and iPad 2 use Absenthe.

For tethered iOS 5.0.1 jailbreak you an use redsn0w 0.9.9 and sn0wbreeze 2.8.

iOS 5.1

For now only tethered jailbreak is available for iPhone 4/3GS, iPad 1 and iPod Touch 3G/4G for iOS 5.1.

The iPhone Dev-Team released jailbreak utility RedSn0w 0.9.9b6 for both Windows and Mac users. The new version offers full iOS 5 jailbreak support for Windows and fixes Location Services issue for iPhone 3GS devices running the 06.15 baseband. This is still a tethered jailbreak for iPhone 4, iPhone 3GS, iPad 1, iPod Touch 3G and iPod Touch 4G:

We've released version 0.9.9b6 of redsn0w, with both a functional fix and cosmetic fix for iOS5 jailbreakers. For iPhone3GS owners with the 06.15 baseband, this redsn0w eliminates the network crash you saw when using Location Services in iOS5 (in fact, you don't even need to disable Location Services anymore during the initial setup). The cosmetic fix is to the visual countdown you see when going into DFU mode.

It's okay to re-run this redsn0w over an existing device jailbroken at iOS5. Just choose "Jailbreak" again and de-select Cydia (in other words, all the checkboxes will be unchecked). If you are lucky enough to have an old-bootrom iPhone3GS, please pre-select the IPSW first (redsn0w can't yet auto-detect the FW version of your old-bootrom 3GS if it's already been jailbroken).

Just as redsnow 0.9.9b5 the new version supports creating custom firmwares with preserving baseband (modem) version for unlock. Unfortunately right now custom firmware functionality works only with Mac version.

If for some reason you don't want to use redsn0w 0.9.9 to jailbreak your iOS 5, here is a good alternative utility - Sn0wBreeze 2.8b8. It can perform a tethered jailbreak for iPhone 3GS, iPhone 4, iPad 1, iPod Touch 3G and iPod Touch 4G.

As usual it will preserve your baseband (modem) version for unlock with ultrasn0w 1.2.4 or Gevey Sim.

The iPhone Dev-Team has released an update to their UltraSn0w unlock bringing support for iOS 5. Remember that NO new basebands are supported in this release. It only adds support for iOS 5 with old basebands.

Here is the list of supported basebands:

iPhone 4: 01.59.00

iPhone 3G/3GS: 04.26.08, 05.11.07, 05.12.01, 05.13.04, 06.15.00.

If have one of the above baseband version and need unlock you can upgrade to iOS 5 without updating your baseband using RedSn0w 0.9.9b5 or Sn0wBreeze 2.8b8.